Download of full BLAST hits from protein BLAST is not currently possible due to a configuration change at NCBI.
It is still possible to get protein BLAST summaries ('Matching region'), but retrieving the 'Full sequence with annotations' from the BLAST options will fail, and so will downloading the full sequence from summary documents. Blasting against and downloading hits from a nucleotide database is not affected by this change and continues to work as usual.
This issue will be fixed in the next updates to R10 and R9. We apologize for any inconvenience this causes in the meantime.